A method for manufacturing uranium dioxide and uranium oxide powders

The method consists in introducing into the reaction zone, a first gaseous reactant constituted by a mixture of uranium hexafluoride with a reducer gas, separately introducing into the reaction zone a second gaseous reactant constituted by an oxygen containing gas and separately introducing into the reaction zone a gas forming a barrier between these first and second gaseous reactants until a sufficient transverse diffusion of the reactants has occurred in said barrier-forming gas. This can be applied to the manufacture of uranium dioxide